This invention relates to the automatic and rapid insertion of letters and other material into envelopes prior to closure and mailing. High throughput insertion machines of this type are exemplified in U.S. Pat. No. 2,325,455 to A. H. Williams. More particularly, the invention concerns an apparatus and method for opening envelope flaps by the use of a rotatable suction cup.
U.S. Pat. No. 3,583,124 to Morrison and assigned to the assignee herein discloses an envelope flap opening apparatus employing a suction cup mounted on a rotatable shaft and positioned alongside an envelope conveying means. After the suction cup makes contact with an envelope flap travelling on the conveying means, a vacuum is applied to the suction cup. The suction cup then engages the envelope flap and rotates about the axis of the rotatable shaft away from the plane of the conveying means, thereby partially opening the flap. A blade member assembly rotates in the direction of the flap until a vertical head portion of a blade member contacts the leading edge of the partially opened flap. The blade member then forces the flap to a fully opened position. While the envelope flap is open, the envelope is rapidly passed toward an insertion plate where letters or other material are automatically inserted. The blade member then rotates back into its original position in preparation for the next envelope.
The envelope flap opening apparatus described above requires that the conveying means and the envelope transported thereon be stopped for a dwell period in the machine cycle. In this particular prior art apparatus the dwell period is necessary to permit the suction cup to engage the envelope flap; to rotate the suction cup and the envelope flap adhering thereto away from the plane of the conveying means; and, to force the flap into a fully opened position. Unfortunately, the dwell period increases production time and lowers output efficiency.
Therefore, an object of this invention is the provision of an efficient envelope flap opening apparatus which reduces the dwell period previously associated with the operation of a rotatable suction cup and a rotatable blade member.
An advantage of the invention is the capability to employ a fixed blade member less susceptible to mechanical complications. Additionally, fixed blade members of different sizes may be easily and advantageously substituted for the blade member installed on the machine. This adapts the envelope flap opening machine to a variety of sizes and shapes of envelopes.